B1.2 - What Happens In a Cell Flashcards
what is DNA (DeoxyriboNucleiAcid)
genetic code that instructs cells on what substances to make
what are chromosomes
a single strand of tightly coiled DNA, located in the nuclei of cells
what are alleles
a different form of gene
what is a nucleus
DNA contained within a nucleur envelope
what is the role of a cell membrane
the cell membrane controls the movement of substances in and out of the cell
what is the role of the nucleus
it carries genetic information
what happens at the cytoplasm
the cytoplasm is where many chemical reactions happen
chromosomes are made out of what chemical?
DNA
what is a section of a chromosome called
gene
what is a gene
a section of chromosome that codes for making particular proteins (and therefore controls inherited characteristic)
what is a double helix
the DNA molecular structure
what is a sugar phosphate backbone
two strands forming the uprights of the ladder. these strands support the base pairs but do not carry genetic information
what are complimentary bases
the two connected bases of the DNA ladder that keep the two strands of DNA molecule together
what are bases
the rungs of the DNA. these are the part of the DNA that carry the genetic information
what are the 4 types of DNA bases
A and T, C and G
what is a polymer
a polymer is a molecule made up of many repeating units. proteins, starch and polythene are all polymers
what is a polynucleotide
a polynucleotide is when its subnits (monomers) are nucleotides
what are proteins
proteins are polymers made up of small molecules (molnomers) called amino acids. different proteins contain different sequences of amino acids
different amino acid chains are folded to form specific 3D shapes. what does this determine
this determines their function
what is needed to make amino acids
nitrogen is needed
where is nitrogen found
nitrogen is found in plants (from air and fertiliser)
what does protein synthesis involve
protein synthesis involves transcription and translation
where does transcription occur
transcription occurs in the nucleus of the cell
what is the process of transcription
1) the section of DNA that codes for a protein ‘unzips’.
2) a complementary strand of messenger RNA (mRNA) forms on one DNA strand.
3) the mRNA peels off and moves into the cytoplasm
where does translation occur
translation occurs in the cytoplams
what is the process of translation
1) the mRNA attaches to a ribosome
2) transfer RNA (tRNA) brings the correct amino acid for each triplet code
what are the 3 components that make up a nucleotide
a sugar, a phosphate group and a base
what is the rate of enzyme action affected by
the rate of enzyme action is affected by temperature, pH, substrate concentration and enzyme concentration
how does high temperature and deviation from the optimum pH affect enzymes
high temperature and deviation from the optimum pH causes enzymes to lose their shape and become denatured
how does low temperature affect enzymes
low temperatures slow down the rate of reaction
how does pH levels affect enzymes
different enzymes have different pH levels depending on where they act in the body
what is the optimum temperature for human enzymes
37 degrees celcius as this is normal human internal body temperature
what happens to enzyme activity if substrate concentration increases
as substrate concentration increases, the rate of enzyme activity increases to the point where all the enzymes present are being used
what happens to enzyme activity if enyme concentration increases
as enzyme concentration increases, the rate of enzyme activity increases to the point where all the substrate present is being used
what are enzymes
enzymes are biological catalysts and increase the rate of chemical reactions inside organisms
what are enzymes made out of
enzymes are made out of proteins
why is the amino acid chain folded
the amino acid chain is folded to make a shape into which substrates (substances) can fit
what is the active site
the active sit is the place where the substrate fits
what can fit into the active site
only substrate molecules with the correct shape and fit
what happens when enzymes lose their shape
enzymes are denatured when they lose their shape
what happenes when an enzyme is denatures
the substrate no longer fits and the enzyme does not work
what is the role of a biological catalyst
it is made up of proteins and speeds up the chemical reactions inside all cells, without being used up
